nVidia is renaming their current generation of video cards to the "GT series".
GT 120 = 9500GT
GT 130 = 9600GSO = 8800GS
GT 140 = 9600GT
The 9600GT is mainstream video for the moment, but when AMD and nVidia release newer cards at the end of the year it will probably drop down to "budget level" performance by most gamers.
The 9600GT / GT 140 direct competitor is the Radeon HD 4670. Both provide more or less the same level of performance, but the HD 4670 consumes 47w of power and does not need an extra power connector. The 9600GT consumes 60w of power and it does require a 6-pin power connector.